Hospital bed having a locally reinforced frame

Abstract

A hospital bed having longitudinal rails, between which levers are supported. The levers are fixed on an axle tube that extends between the two longitudinal rails. The longitudinal rails are locally reinforced with respect to their wall thickness on the side situated adjacent to the axle tube by means of reinforcing plates welded thereto. A round rod extends through through-holes in the two longitudinal rails and the axle tube. For this purpose, the longitudinal rails are provided with through-holes that extend through the reinforcing plate.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This patent application is the national phase of PCT / EP2008 / 001050, filed Feb. 12, 2008, which claims the benefit of German Patent Application No. 102007014101.9, filed Mar. 21, 2007.FIELD OF THE INVENTION[0002]The present invention relates generally to hospital beds, and more particularly to hospital beds that are convertible from a normal bed position into a sitting chair position.BACKGROUND OF THE INVENTION[0003]Hospital beds are typically composed of a floor-standing lifting mechanism on which a bed frame is arranged. The lifting mechanism makes it possible to adjust the height of the bed frame from a normal bed height to a nursing height so that patient care administered by the nursing staff is simplified. The actual bed frame is divided into several sections that can be moved relative to one another in order to elevate the individual body sections to a greater or lesser extent.[0004]Due to such multiple pivoting and moving functions...

AI Technical Summary

Benefits of technology

[0007]In light of the foregoing, it is an object of the invention to provide a hospital bed in which the axles are supported in a relatively simple manner between rectangular tubes that form the longitudinal rail.

[0013]If a single round rod is used that extends through both rails and the axle / shaft, particularly favorable conditions with respect to the bending load of the round rod are realized because a freely projecting inner end, as occurs with driven-in knurled bolts, is avoided. The round rod is clamped in position on both ends and does not project freely on one end like a knurled bolt. This also reduces the load on the edge of the through-hole because the bending strength reduces tilting of the round rod in the through-hole. Consequently, the outer section of the through-hole is also used for the support such that the surface pressure on the bearing side is significantly reduced.

[0014]In the hospital bed of the invention, the reinforcing plate provided on the bearing side functionally replaces the bearing bushing used thus far, i.e., the space between the two parallel walls of the longitudinal rails does not contain any other structural elements. Adequate load conditions are realized if the reinforcing plate is integrally connected to the respective surface of the longitudinal rail. The integral connection can be produced by soldering the reinforcing plate or by welding the reinforcing plate at its edges. The reinforcing plate may be square, for example, such that the orientation during the installation on the longitudinal rail is significantly simplified. An adequate load transfer to the reinforcing plate also is achieved if the through-hole is produced after attachment of the reinforcing plate.

[0016]An advantageous support of the axle or shaft on the round rod is realized if the ends of the tubular axle or shaft have reduction sleeves with openings adapted to the outside diameter of the round rod. With the aid of at least one frictionally engaged retaining ring, the round rod can be held so that it cannot be axially displaced.

Problems solved by technology

Due to such multiple pivoting and moving functions within the hospital bed, there still remains the recurring problem of rotatably supporting an axle or shaft between two longitudinal rails.

Naturally, this also affects the welding seam.

However, it has been found that such mounting method is reliable only if the components are manufactured with very strict tolerances.

During the rotation of the axles, a rotating load occurs that results in compression of the joint between the bolt and the bushing, which causes the material to creep in the region of the knurling so that the bolt becomes loose.

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